I thought the noise cancelling was good, but there was a price to pay for it. The clamping force was pretty high, so I didn't find them very comfortable. (If you wear glasses like I do, this is a real issue.)
The biggest disappointment for me was the audio. For $200, I expected great audio, and to my ears, it just wasn't there. Deep bass was non-existent, and there appear to be holes in the audio EQ. Listening to some music, it sounded like some of the instruments had been muted.
Not what I expected from a top-end Sony headphone.